Slides for binding a margin of a calendar, poster, document, banner, or other wall hanging are known in the art. Examples of prior art slides are shown in FIGS. 1–4, and such a slide 1 is generally an elongated strip of roughly V-shaped sheet metal. The vertex 2 of the elongated V-shaped strip of sheet metal separates the two sides or legs 3,4 of the V-shaped strip. Typically, one side or leg 3 of the V-shaped strip is shorter or narrower, and the other side or leg 4 is longer or wider. The slide 1 also typically contains a hanger 5 which, as shown in FIG. 1, is a separate piece attached to the V-shaped sheet metal strip or, as shown in FIG. 2, is part of the V-shaped sheet metal strip. The hanger 5, shown in FIG. 1, is typically made out of plastic and is staked or attached at the approximate longitudinal center of the metal strip by one or more sheet metal burrs or rivets 6. The V-shaped strip of sheet metal is attached to a calendar by folding or crimping it onto the margin of the calendar. The hanger 5 can then be used to hang and display the calendar at a desired location, e.g., a wall. The surface of the slide that is visible when it is displayed is often painted to prevent oxidization and for aesthetic purposes. Examples of slides are shown in U.S. Pat. Nos. 1,906,024; 2,042,912; and 6,042,319, each of which are hereby incorporated by reference.
The prior art also discloses an old version of a slide that includes two indentations in the longer, wider side or leg 4 of the V-shaped sheet metal strip, as shown in U.S. Pat. No. 2,042,912. The indentations in the slide disclosed in that patent project outwardly, away from the associated leg 3 and are close to the ends of the slide.
There are a number of problems with these prior art slides. First, the slides have a tendency to stick together when they are stacked or nested tightly together. This is particularly problematic when a binding or tinning machine is being used to install a slide on a calendar.
Traditionally, an operator manually attached a slide to the margin of a calendar, one slide at a time, using a tinning machine. Accordingly, while stuck-together slides could be an annoyance, and could take extra time to separate, an operator could at least see the problem and separate the slides. More recently, however, newer binding or tinning machines have been developed with magazines or hoppers which hold a supply of the slides nested together. Accordingly, now when slides stick together, they not only become more difficult to feed from the magazine or hopper, but there is also an increased tendency for multiple stuck-together slides to be fed into the tinning station, causing the machine to jam or malfunction.
Another problem with the traditional slide is that, as shown in FIG. 3, when the slides are stacked or nested together, the attached hanger 5 and the associated rivets or burrs 6 tend to act as a fulcrum and, as the stack grows, cause one end of the slides to fan or bow out. This lack of stackable uniformity can increase the space required for shipping or storing the slides. In addition, when the slides fan, bend, bow, or curl, the capacity of the binding or tinning machine magazine or hopper is reduced. Decreasing the capacity of the tinning machine's magazine means that it must be more frequently refilled, thus decreasing the overall efficiency and productivity of the binding operation.
Additionally, when the slides shown in FIGS. 1 and 4 are stacked or nested together in a tinning machine magazine or in the case of shipment or storage, the protruding indentations, bulges, burrs or rivets 6, which often have rough edges, can scratch the painted exterior of an adjacent slide, causing unsightly marks and contributing to either a less than desirable end product, or a product that must be discarded due to quality control standards. For example, if the concave indentations are placed, as shown in the prior art '912 patent, near to the longitudinal ends, the slide will have a tendency to medially sag, bend, or bow. Thus, this has the undesirable effect of creating a nonuniform stack of slides which results in a decreased tinning machine magazine capacity, increased difficulty in feeding the slides from a magazine, and increased likelihood of feeding malfunctions. Moreover, when the longitudinal center sags, bends, or bows, there is an increased tendency for the burrs or rivets to contact and scratch or mar the painted or coated exterior of the second wider bend portion. Such scratching or marring, especially at the visible center, when displayed, of the slide may, based on quality control standards, require the slide to be discarded, or sold at a lower price.
Moreover, when a slide with concave indentations is used in a binding or tinning machine, the crimping bars of the binding machine move directly against the painted and protruding surface of the concave indentations and tend to scratch or remove the paint from such protrusions.